Spiral or Rake Mechanical Classifiers
As a important separation equipment in beneficiation plant , Spiral or rake classifiers are semirectangular tanks with parallel sides (sides may flare somewhat toward the overflow end) and a sloped bottom. Inside the tank, a rake or a spiral mechanism conveys coarse material upward to a sands return chute and back to ball mill . Figure 1 shows schematics of a rake classifier and the more modern spiral classifier . General Characteristics of classifier. Take L to be the length of the classifier. Feed enters at a point that is about 0.6 L (high weir type) or 0.5 L (overflow end of spiral submerged) or 0.3 L (low weir type) from the overflow weir (the overflow weir is a movable baffle plate at the overflow end, the height of which can be adjusted to control pool area). Spirals are preferred to rakes because spirals cost less to maintain. Either rakes or spirals move coarse sand out of the tank. Rakes employ a repetitive rectangular trajectory whose long dimension is parallel ...